32results about How to "Low hydrothermal reaction temperature" patented technology

The invention discloses a graphene/ stannic oxide nanometer compounding resistance type film gas sensor, which takes ceramics as a basal body. The surface of the ceramic basal body is photo-etched and evaporated with multiple pairs of interdigital gold electrodes, and is coated with gas-sensitive films of graphene and stannic oxide nanometer composite, and the manufactured resistance type film gas sensor has the advantages of simple manufacturing process and low cost. The gas-sensitive film is composed of a grapheme namosheet layer in a three-dimensional nano-structure and stannic oxide crystal particle composite with an orientated growth characteristic, the introduction of the graphene can favorably reduce the resistance of sensor elements, and the formation of the three-dimensional nano-structure can obviously enhance the specific surface area of the composite, thus the absorption and the diffusion of the gas can be promoted so as to greatly enhance the room temperature gas sensitive response sensitivity of elements. The graphene/stannic oxide nanometer compounding resistance type film gas sensor has the characteristics of high response sensitivity to low concentration ammonia, fast response, favorable recovering performanc, capability of carrying out the detection at the room temperature, and the like, which can be widely applied in the agricultural and industrial production process, and the room temperature detection and control of the concentration of ammonia in the atmospheric environment.

The invention relates to perovskite composite oxide LaFeO3 monodisperse micrometer hollow balls and a preparation method thereof, and belongs to the technical field of micro nanometer functional materials. The micrometer hollow balls are in a monodisperse state, the outer diameter of each micrometer hollow ball is between 1 and 7 micrometers, and the micrometer hollow balls are in a perovskite crystalline phase. The preparation method comprises the following steps of: stirring a mixed solution containing urea serving as an additive, citric acid serving as a complexing agent, deionized water serving as a solvent and metal nitrate uniformly, transferring the mixed solution to an autogenous pressure kettle, putting into a constant temperature box, keeping temperature for a certain time, cooling naturally, performing suction filtration on the obtained products, drying, grinding, and roasting at high temperature to obtain the highly-monodispersed LaFeO3 micrometer hollow balls. According to the preparation method, a template is not needed to be utilized, the reaction time is short, the preparation process is environment-friendly, and the operation is easy to implement.

The invention provides a preparation method of indium tin oxide nano powder, including that: indium chloride tetrahydrate and stannic chloride pentahydrate with the mol ratio of indium and stannum of 9-10:1 are dissolved by deionized water, ethidene diamine solution is added, and even mixing is carried out to obtain reaction solution; the reaction solution is placed into a kettle, reaction is carried out at 150-200 DEG C for 3-18 hours, and natural cooling to room temperature is carried out, so as to obtain intermediate product; the intermediate product is separated by centrifugation, washed by deionized water and absolute alcohol and dried at 40-70 DEG C for 6-24 hours, so as to obtain ITO precursor; the obtained ITO precursor is calcined and then heated to 400-550 DEG C from room temperature at heating rate of 2-8 DEG C per minute, heat preservation is carried out for 1-3 hours, and natural cooling to room temperature is carried out, thus obtaining ITO nano powder. The prepared ITO nano powder has high purity, small grain and uniform component, and synthesis technology and the required production equipment are simple, and industrialized production is easy to realize.

The invention discloses an NiFeMo ternary electrolytic water electrode and a preparation method thereof. Firstly, iron salt, nickel salt, urea and NH4F are used as raw materials under a low-temperature hydrothermal condition to prepare NiFe-LDH/NF, then NiFe-LDH/NF and a compound containing molybdenum are subjected to a low-temperature hydrothermal reaction to obtain Ni-Fetrace@NFM/NF, then Ni-Fetrace@NFM/NF is placed in a flowing reducing atmosphere for heat treatment for a certain time, and a final material of Ni/NiFeMoOx/NF is obtained; and in the process, an LDH substrate is reduced to Ninanoparticles, and mutually cross-linked with NiFe-MoOx generated by reduced molybdate to form a composite material with a hierarchical porous nanosheet structure. The hierarchical porous nanosheet structure facilitates bubble diffusion, a formed alloy is cross-linked with MoOx and combined with a conductive substrate to have excellent electrical conductivity, and in the way, the material has excellent reaction kinetics; and NiFe-MoOx with the high hydrogen evolution activity and the Ni nanoparticles with the high hydrogen evolution activity both endows the material with excellent hydrogen andoxygen evolution properties, and then catalytic performance of all electrolytic water with application prospects is obtained.

The invention belongs to the technical fields of inorganic nonmetallic nanomaterial preparation and water purification environmental protection, in particular to high-specific surface area low-isoelectric point nano zirconium dioxide and a preparation method and application thereof in removing arsenic. The nano zirconium dioxide has the crystallized specific surface area of 161.8m<2>/g, the amorphous specific surface area of 327.1m<2>/g and the isoelectric point of about 3 to 4. The nano zirconium dioxide has higher arsenic-removing capacity, the saturated adsorption capacity of a crystallized sample exceeds 47mg/g, and the saturated adsorption capacity of an amorphous sample exceeds 83mg/g. ZrOCl2.8H2O, water and ammonia water serve as precursors of a hydrothermal reaction, and the method comprises the following steps of: performing hydrothermal reaction to obtain a zirconium oxide precipitate; washing, drying and grinding to obtain amorphous zirconium dioxide powder; and calcining to obtain the crystallized zirconium dioxide material. The process of preparing the nano zirconium dioxide is simple, the high-specific surface area low-isoelectric point nano zirconium dioxide can be obtained, and a novel arsenic removing material is provided for purification of arsenic-containing sewage and environmental protection.

The invention discloses a method for preparing a xonotlite crystal whisker by using an active silica raw material and a calcium carbonate raw material. The method comprises the following steps: (1) grinding the active silica raw material and the calcium carbonate raw material to obtain active silica powder and calcium carbonate powder; (2) batching the active silica powder or/and the calcium carbonate powder obtained in the step (1), adding industrial water and directly putting into a closed reaction unit to perform a synthesis reaction by controlling the heating rate, the reaction temperature and the reaction time; and (3) filtering and drying, namely dispersing reaction products obtained in the step (2) to obtain the xonotlite crystal whisker. The xonotlite crystal whisker prepared by the method disclosed by the invention is relatively large in crystal grain, large in length-diameter ratio, high in strength, good in stability, wide in application range and beneficial to promotion and application.

The invention relates to a cathode material, alpha-Fe2O3, of a high-capacity lithium ion battery and a preparation method for the cathode material. According to the preparation method, soluble trivalent molysite and an alkali metal hydroxide easy to dissolve are adopted as raw materials, and the hematite alpha-Fe2O3 is prepared by a hydrothermal method. The preparation method comprises the following specific steps that: 1) aqueous solution of the trivalent molysite with molarity being 0.5mol/L-2mol/L and aqueous solution of the alkali metal hydroxide easy to dissolve with molarity being 2mol/L-6mol/L are prepared; 2) the aqueous solution of the trivalent molysite and the aqueous solution of the alkali metal hydroxide obtained in the step 1) are mixed to generate suspension, the suspension is stirred for certain time, and then ammonia water drops into the suspension, so that the pH value of the suspension is adjusted to be 9-13; and 3) the suspension obtained in the step 2) is poured into a hydrothermal reaction kettle which can be airtight, the hydrothermal reaction kettle is put into an oven to be heated at a temperature of 160 DEG C-200 DEG C and then is subjected to thermal insulation for 3 hours to 20 hours, and after the reaction is finished, a product is subjected to solid-liquid separation, washing and drying so as to obtain the alpha-Fe2O3. When serving as the cathode material of the lithium ion battery, the alpha-Fe2O3 prepared by the method has higher specific capacity and better cycling stability. According to the method, the operation is simple, the cost is low, additives are not required, and the product quality is stable.

The invention relates to a hollow-structure ferrous sulfide (at) carbon in-situ composite material and a preparation method and application thereof. The preparation method comprises the following steps: 1, dissolving ferrous sulfate and glycerin in water, then dropwise adding alkali liquor till sediment appears, stopping dropwise adding, conducting stirring at the room temperature, and then conducting suction filtration, washing and drying to obtain a rod-like ferrous precursor; (2) dispersing the ferrous precursor in water, adding an organic sulfur source, stirring to react for at least 1 hour, heating to 130-150 DEG C to perform hydrothermal reaction, naturally cooling to room temperature, and performing suction filtration, washing and drying to obtain a ferrous sulfide precursor; and calcining the ferrous sulfide precursor, and cooling to obtain the ferrous sulfide (at) carbon in-situ composite material with the hollow structure. The ferrous sulfide (at) carbon in-situ composite material with the hollow rod-shaped structure is obtained through a template-free method and is applied to the potassium ion battery as an electrode active material, the obtained battery is long in cycle life and good in potassium storage performance, and a negative electrode structure is stable and does not pulverize or fall off.

The invention provides a low-temperature hydrothermal method for preparing nano lithium iron phosphate. The method comprises the following steps: weighing lithium phosphate, ferrous sulfate and a reaction aid according to a certain proportion; the preparation method comprises the following steps: dissolving ferrous sulfate in a proper amount of deionized water, transferring to a hydrothermal reaction kettle, then adding lithium phosphate and a reaction aid to obtain a solid-liquid mixed suspension, carrying out ultrasonic-assisted dispersion for a certain time, then heating the reaction kettle at a certain temperature, and carrying out heat preservation for a certain time; and washing the product obtained after hydrothermal treatment with deionized water, and drying to obtain the nano lithium iron phosphate. According to the invention, the hydrothermal reaction temperature is effectively reduced, the equipment requirement is reduced, the equipment investment is reduced, and the production safety is improved.